CAJ | 학술논문

通过控制排水措施适当提高地下水位，可以增加半湿润灌区作物对浅层地下水的利用量，缓解灌溉水量的不足。然而，灌区地下水的含盐量一般较高，对盐分在作物根区的过分累积，所需淋洗水量很难得到保证。考虑到半湿润灌区具有一定量的降雨，可能对土壤盐分产生淋洗作用，建立了一个控制排水条件下降雨洗盐计算模型，并以某半湿润灌区盐碱地改良区为例，利用田间水文模型DRAINMOD预测出多年（1951—2005）田间水量平衡逐日变化过程，连续计算控制排水以及不同补充灌溉条件下根层土壤盐分多年的动态过程。结果显示，当地下水控制埋深为1.2 m时，在无灌溉条件下，研究区降雨虽能起到一定的淋洗作用，但根区盐分会随着时间的推移逐渐累积。当补充灌溉量在150 mm以上时，研究区降雨能够有效控制土壤盐分，使根区土壤在多年条件下达到良性的水盐平衡。所以，在与研究区类似的半湿润地区，通过控制排水措施合理调控地下水埋深，并充分利用天然降雨的淋洗功能，不仅可以维持灌区良性的水盐平衡，而且可以提高水资源利用效率。
통과공제배수조시괄당제고지하수위，가이증가반습윤관구작물대천층지하수적이용량，완해관개수량적불족。연이，관구지하수적함염량일반교고，대염분재작물근구적과분루적，소수림세수량흔난득도보증。고필도반습윤관구구유일정량적강우，가능대토양염분산생림세작용，건립료일개공제배수조건하강우세염계산모형，병이모반습윤관구염감지개량구위례，이용전간수문모형DRAINMOD예측출다년（1951—2005）전간수량평형축일변화과정，련속계산공제배수이급불동보충관개조건하근층토양염분다년적동태과정。결과현시，당지하수공제매심위1.2 m시，재무관개조건하，연구구강우수능기도일정적림세작용，단근구염분회수착시간적추이축점루적。당보충관개량재150 mm이상시，연구구강우능구유효공제토양염분，사근구토양재다년조건하체도량성적수염평형。소이，재여연구구유사적반습윤지구，통과공제배수조시합리조공지하수매심，병충분이용천연강우적림세공능，불부가이유지관구량성적수염평형，이차가이제고수자원이용효솔。
Properly raise water table with controlled drainage may increase shallow groundwater which can be used by crops,mitigating the water shortage in subhumid irrigated areas. However,salinity in groundwa?ter over there is generally higher, and increasing use of shallow groundwater may speed up salt accumula?tion in the root zone and shorten the salt leaching cycle;this is not desired in these areas because the leaching water can hardly be ensured during the required period. Considering in the subhumid irrigation ar?eas there are certain amount of rainfall that may produce leaching effect for salinity control, an analytical model was developed for calculating salt leaching cycle under controlled drainage. The model was tested subsequently through a case study in a subhumid irrigation area in which soil was reclaimed from saliniza?tion. With the daily water balance predicted by the field hydrology model-DRAINMOD, we calculated the salt accumulation in the root zone over a long term period (1951-2005) under controlled drainage and dif?ferent supplemental irrigation depths. The results show that when groundwater depth is controlled at 1.2 m, rainfall has some effect on salt leaching even without irrigation;but soil salinity grows with time in the root zone. When the supplementary irrigation depth is greater than 150 mm, rainfall can effectively control the root zone salinity to reach a favorable salt balance in the case study area. Findings from this research indicate that in subhumid irrigation areas, considering the leaching effect of rainfall, proper water table management with controlled drainage can effectively control soil salinity for crop production and improve wa?ter use efficiency.